“…However, most articles dealing with sustainability do not provide an explicit definition of the concept of 'sustainability' (Gaikhorst et al, 2018;Prenger et al, submitted). A number of dimensions have been mentioned in different articles however: sustained implementation of the core components of the intervention (e.g., Andreou et al, 2015aAndreou et al, , 2015bDrits-Esser et al, 2017;Gaikhorst et al, 2017;Kafyulilo et al, 2016); continuation of the intervention on the long run, or results that are maintained or continue to improve (e.g., Bean et al, 2015;Elder & Prochnow, 2016;Ferguson et al, 2011;Stringfield et al, 2008); becoming integral part of daily school routines (e.g., Bambara et al, 2012;Bean et al, 2015;Elder & Prochnow, 2016;Tam, 2009); scaling up of results (e.g., Dekker & Feijs, 2005); and adaptiveness (Benz et al, 2004;Deaney & Hennessy, 2007a, 2007bElias, 2010). These elements will be discussed in order to define sustainability for this study.…”